In a situation in which factors in the variation of voltage, such as distributed power sources and an electric vehicle charging station, are associated with a power distribution line, there is a need for an apparatus for controlling variation in voltage in a power distribution system.
Apparatuses for controlling variations in voltage in a power distribution system may include, for example, a tap switching device when a load is applied, and a capacitor bank. These apparatuses are problematic in that it is difficult to solve a voltage problem in an overall power distribution line because voltage can be controlled only on a bank basis.
In order to solve the problem, a device, such as a line voltage control device, is installed in the middle of a power distribution line. However, it is difficult to apply such a line voltage control device to a current system within a short period because the line voltage control device is expensive.
Furthermore, in methods for solving a voltage problem in a power distribution line, circulation current that may occur upon the switching of a switch is not taken into account, and an operation in conjunction with a tap switching device is not performed when a load is applied.